Question

In a famous experiment, Matthew Meselson and Franklin Stahl grew E.coli cells in a medium containing only the "her isotope of nitrogen, SN. These cells were then transferred to a medium with the "light" isotope of nitrogen, "N. The results of the experiment supported the hypothesis of semiconservative replication, which was proposed by Watson and Crick. Heavy DNA ('N DNA), hybrid DNA, and light DNA (N DNA) can be separated by centrifugation. If cells containing 1SN DNA are transferred to a medium with only N NHC as a nitrogen source, what percent of daughter molecules are composed of hybrid DNA after 2 generations? daughter molecules: % Enter numere value Predict what percent of daughter molecules would be composed of hybrid DNA if DNA exhibited conservative replication. That is, if a daughter DNA molecule were composed of newly synthesized DNA only. daughter molecules: MacBook Pro 18 90 $ 2 3 4 5 6 & 7 8 9 0 W E R T Y U I 0 Р 5 D F G H J K L X C V < B N > M

Answer 1

Answer =

If cells containing 15N DNA are transferred to a medium containing with only 14N, NH4Cl , percent of daughter molecules are composed of hybrid DNA molecules after 2 generations are = 50%

daughter molecules =50%

Explanation =

auce transferred to are DNA after 15N, ISM After 2 4 all light 15 MIN 2 ONA steands If cell containing 15N ONA medium with only 14N NHCI as miteogen sous ce) the composed Percent of daughter molecules of hybeid DNA 2 genegations : 507 generation o generation there is synthesis of 4 daughter steands. out of 4: S4 generation 1 2 DNA strands are hybeid. Hybeid DNA Hybeid DNA % of daughter molecules composed of hybeid DNA- "M 4 MIN after 2 generations 50% 15 Nita 14N IN generation Hey beid Hybeid light DVA = 214 1 w 2 light DNA DNA DNA Scanned with CamScanner

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percent of daughter molecules are composed of hybrid DNA molecules , if DNA exhibited conservative replication. = 0%

Explanation =

Percent of daughter molecules would be composed of hybeid DNA, if DNA exhibited replication . 0% conservative ISN ISN ☆ generation : 0 ISNIS => generation "L" light DNA- Add DNA: 15 NISN 14N 14M 140 14N NAM 14 2 => generation = formation of 4 - steunds Heavy DNA light DNA After end genes ation there is daughter 1 DNA molecules DNA molecules light daughter molecules would be composed of Mybeid DNA Heavy- - 3 19 0% CScanned